Well I thought the portable hole is two dimensional so I don't know how you could break that. And no I don't think there are. There are rules about putting them in antimagic fields though in which case you can't access them anymore.
Question though. If you had a huge 40 by 40 by 40ft room filled with cursed lead and a smaller room with floor walls ceiling covered in quicksilver would the quicksilver room be affected by the anti magic?